Lost atoms

Hi.
I'm new to MD and lammps.
I'm doing a simulation of a PEG SAM on a perfect gold 111 surface in
water using charmm FF.
I have done the minimization and then the equilibration (in npt
condition and 3D periodic conditions) of the system ( 2 ns).

Now I want to do the main run but i can't do it, because I always
obtein the error :

ERROR: Lost atoms: original 48510 current 48509 (thermo.cpp:386)

For every simulation this error come at a different timestep.
I don't understand why I get this error.

Thank you.

My input file is :
####################
clear
newton off
units real
neighbor 2.0 bin
neigh_modify delay 4
boundary p p f

atom_style full
bond_style harmonic
angle_style charmm
dihedral_style charmm
pair_style lj/charmm/coul/long/gpu 12 13
pair_modify mix arithmetic
kspace_style pppm 1e-4
kspace_modify slab 3.0
package gpu force/neigh 0 0 1.0
read_data AUOEGH2O.data
group oro type 9
group acqua type 3 7

special_bonds charmm
fix 1 all shake 1e-6 500 0 m 1.0 b 2 5 7 a 12
fix 2 all nvt temp 302.0 300.0 1
fix parete acqua wall/reflect zhi EDGE

thermo 250
thermo_style multi
timestep 2

restart 7000 AUOEGH2O.restart
dump 1 all atom 500 AuOEGH2O.dump
dump 2 all xyz 50000 scatolaAUOEGH2O.xyz
dump 3 all xtc 250 AUOEGH2O.xtc
dump 4 all custom 50000 dump.Velocit.* id vx vy vz
run 2000000

Hi.
I'm new to MD and lammps.
I'm doing a simulation of a PEG SAM on a perfect gold 111 surface in
water using charmm FF.
I have done the minimization and then the equilibration (in npt
condition and 3D periodic conditions) of the system ( 2 ns).

Now I want to do the main run but i can't do it, because I always
obtein the error :

ERROR: Lost atoms: original 48510 current 48509 (thermo.cpp:386)

For every simulation this error come at a different timestep.
I don't understand why I get this error.

please read the documentation about this *very* common
error messages. it provides some suggestions.

my first suggestion would be to look at whether previous
runs generate "dangerous builds" in the neighbor list statistics
and try more conservative settings for neighbor list builds and
time step.

axel.